1. Field of the Invention
The present invention generally relates to a bicycle electrical generator hub mounted in the center part of a wheel of a bicycle. More specifically, the present invention relates to a bicycle gearshift system that is driven electrically and equipped on the rear hub part of a bicycle frame.
2. Background Information
Some bicycles are equipped with gearshift mechanisms such as derailleurs or hubs with internal gearshifters. Electrically powered gearshift devices are already known. In conventional gearshift systems that include electrically powered gearshift mechanisms, automatic gearshift control, for example, is performed by the electrically driven gearshift mechanism according to the speed of the bicycle, or gearshift control is performed through the operation of a gearshift operating part. See, for example, Japanese Patent Laid-Open No. 2003-011879.
Specifically, a gearshift operating part is equipped on the bicycle, a gearshift control part is mounted on the frame, and an electrical generator hub is used as a power supply. Gearshift systems equipped with motor units that electrically drive the gearshift mechanisms have been disclosed as conventional technologies. For example, gearshift systems where the motor units and the gearshift mechanisms are connected by gearshift cables, and gearshift systems where the electrically powered gearshift mechanisms are connected with control devices over electrical cables have been provided.
In a conventional gearshift system, not only are the gearshift operating part and the gearshift control part connected by a wire, but also the gearshift control part and the electrically powered gearshift mechanism or motor unit are connected by a wire as well. In addition, when shifting gears automatically according to the bicycle speed, bicycle speed signals have been obtained from signals from a dynamo equipped within a hub in the aforementioned conventional gearshift systems. However, when a normal battery, or the like, is used as the power supply, it has been necessary to connect also the speed sensor and the gearshift control device with a wire as well.
In view of the above, it will be apparent to those skilled in the art from this disclosure that there exists a need for an improved bicycle electrical generator hub mounted in the center part of a wheel of a bicycle, a bicycle gearshift system equipped on the rear part of a bicycle frame, a bicycle derailleur that is driven electrically and mounted on a bicycle frame, and a bicycle with such parts. This invention addresses this need in the art as well as other needs, which will become apparent to those skilled in the art from this disclosure.